Battery units are commonly used for a variety of purposes. For example, battery units are often used in portable electronic devices such as remote control devices for automobiles, allowing a user to lock or unlock car doors and perform a variety of other functions without using a key. Such devices have become increasingly popular in recent years, and there has arisen the need for an improved process of manufacturing battery units in an efficient and inexpensive manner while achieving a high degree of reliability. More particularly, there has arisen the need to decrease the cost of manufacturing and increase the quality of such devices through the use of automated processes.
Since the size of portable electronic devices is continuously decreasing, the space requirement of the battery unit is of particular importance. The smaller the battery unit, the more compact the portable electronic device can be.
There are currently a number of types of battery units and methods for manufacturing the same, but each type of unit and method of manufacture has certain drawbacks. For example, one type of prior art battery unit, shown in prior art FIG. 14 and Japanese Publication No. P2000-149898A, reveals a circuit board 100 having a cylindrical-shaped indentation 102 for the placement of a battery. A first electrode 104 runs across the bottom of the indentation 102, while a second electrode 106 extends from the circuit board 100 over the top of the indentation 102. In this arrangement, however, the battery must be slid underneath the second electrode 106. This step can be difficult to accomplish with an automated system, resulting in an increased amount of assembly time and cost of automated equipment. Furthermore, in the event that the orientation of the battery is inadvertently reversed, the resulting reverse bias can cause damage to the circuit inside the unit. The likelihood of such a reverse bias occurring is also increased when a person, rather than an automated system, must place the battery into the unit or when an individual replaces a dead battery.
In a second prior art arrangement, as shown in FIG. 15 and Japanese Publication No. H5-50655, a battery sits flat in a region 206 on the surface of the circuit board 200. A first contact 202 is positioned to wrap partially around the battery, forming a vertical wall that is no higher than the battery is thick. This wall is anchored at both ends by parts of the wall that lie flat on the circuit board 200. A second contact 204 lies flat on the circuit board 200, touching the underside of the battery. Under this arrangement, however, it is possible for the battery to slide out of position before the case is completely assembled. Additionally, the vertical wall that is used to make up a portion of the first contact 202 can be easily damaged by a mispositioned battery during assembly.
Another type of portable battery unit is currently produced by Alps Automotive and includes a printed circuit board with a plurality of through holes formed therein. Positive and negative battery terminals are placed on the circuit board to correspond with these through holes, and the positive and negative battery terminals are hand-soldered to the printed circuit board. Although the end product is relatively robust in design, the process for placing and soldering the positive and negative battery terminals to the printed circuit board may be manually intensive and time consuming. If the placing and soldering were automated, it would be more difficult and more expensive. In particular, the placement and soldering of the terminals would be a separate operation after placing and soldering the electronic components. Also, the positive terminal has a footprint of approximately twice the area of this design.